The present invention relates to a continuous treatment apparatus for a viscous material which is preferable for the continuous condensation polymerization, for example, of polyethyleneterephthalate and polycarbonate.
In general, in continuous treatments such as the kneading and reaction of a viscous material, it is required to minimize dead space in the apparatus and provide operation as similar to a piston flow. To meet these requirements, there have been various inventions in which a long cylindrical vessel is used and two rotational shafts having agitator blades are provided thereon in the longitudinal direction. For example, Japanese Patent Publication No. 29019/1977 discloses an apparatus in which paddle vanes are arranged in several stages so as to enable the scraping of the entire inner surface of a vessel and ensure that there is little dead space therein. However, as shown in FIG. 22, when the viscosity of the liquid being treated rises to several thousand poise, this apparatus has the problem that a lump of highly viscous liquid 31 adhering to the surfaces of rotational shafts 30 rotates together with the surfaces of te rotational shafts 30, resulting in scaling, etc. Namely, the liquid 31 temporarily adhering to the surfaces of the rotational shafts 30 has a lower speed in the liquid, compared with liquid adhering to agitator blades 32, and, since the liquid has a weak shear force, it is difficult to renew and so rotates adhered to the shaft surfaces.
An attempt has been made to remove these rotational shafts 30 so as to reduce this co-rotation. Japanese Patent Publication No. 40732/1974 proposes an apparatus in which the outer peripheries of discs with holes are connected so as to omit the need for the rotation shafts 30. This apparatus produces no corotation with the rotational shafts 30, but has the problem that, as shown in FIG. 23, highly viscous liquid 34 adhering to the surfaces of plate-shaped agitator blades 33 flows with difficulty and rotates together with the agitator blades 33, resulting in scaling, etc. In other words, if bodies having plane surfaces such as plates are rotated in a liquid of a high viscosity, as shown in FIG. 23, the highly viscous liquid 34 rotates together with the agitator blades 33 as the agitator blades 33 rotate, while the highly viscous liquid which has adhered temporarily to the surfaces of the plates adheres to the surfaces of the agitator blades 33 and rotates therewith, because of the weak shear force except at the edges of the agitator blades 33.
As described above, the adhesion of a high viscous liquid to the surfaces of rotation shafts and plate-shaped agitator blades results in a deterioration in the quality of the liquid being treated due to heat aging.
A conventional continuous treatment apparatus for a highly viscous material, as described in Japanese Patent Publication No. 29733/1985, is provided with an extraction pump in a lower portion of an outlet nozzle for the liquid being treated and thus needs a drive apparatus for extraction which is separate from the driving of agitator blades in the vessel body. Furthermore, the conventional apparatus also needs a quantitative supply apparatus for the liquid being treated which is separate from the vessel body.
The above-described prior art necessitates a separate drive apparatus for the agitator blades in the vessel body, the extraction pump, and the supply pump, and so has the problems because of its complicated structure and a high production costs.